BLRD Research Career Scientist Award Application

糖尿病是终末期肾病的头号原因，约占 在美国的案例。超过3400万美国人患有糖尿病。它在18岁和18岁以下的人群中流行 年纪更大了。退伍军人人口属于这一年龄段。在65岁以上的退伍军人中， 大约27%的人患有糖尿病。最近的一项研究表明，糖尿病患者的肾脏 疾病使心血管死亡的风险增加87%。每三个糖尿病患者中就有一个患上糖尿病 肾病(DN)。糖尿病肾病早期病理改变累及肾脏，尤其是肾小球肥大和 基质蛋白的膨胀。我们研究的重点是探讨信号转导机制。 导致糖尿病肾病的进展。为了测试我们的概念，我们同时使用肾小球系膜和近端 培养中的肾小管上皮(PTE)细胞以及表现肾脏病变的糖尿病小鼠和大鼠模型。在……里面 在肾脏，高水平的转化生长因子-b(TGFb)介导了许多高血糖的病理效应。 因此，结合高糖的作用，我们研究了TGFb在系膜细胞中的信号机制 和PTE细胞。我们是第一个发现高糖降低肿瘤抑制因子表达的人 PTEN蛋白(10号染色体缺失的磷酸酶和张力蛋白同源物)在这些细胞和肾脏中的表达 糖尿病小鼠和大鼠的组织。我们发现高糖的这种作用是由TGFb介导的。在……里面 在研究其机制时，我们首次报道了多个microRNAs，如miR-21、miR-26 和miR-214在糖尿病肾脏中显著增加，调节高血糖-和TGFb- 诱导PTEN的抑制。事实上，我们发现这种对PTEN表达的抑制导致了 Akt激酶的激活导致mTORC1(雷帕霉素复合体1的机制靶点)的激活。MTORC1 促进系膜细胞和PTE细胞肥大，以及基质蛋白纤维连接蛋白和I型胶原的表达 A2可导致糖尿病肾病大鼠肾脏肥大和纤维化。事实上，我们发现雷帕霉素可以改善并发症。 糖尿病肾病包括1型和2型糖尿病小鼠的蛋白尿。由于上述基因表达增加 MicroRNAs参与PTEN抑制/Akt激酶介导的mTOR激活，我们的研究打开了 抗miR治疗在糖尿病肾病中的新应用。雷帕霉素介导的mTORC1致病基因的完全抑制 有害的临床后果。小鼠近端肾小管mTORC1缺失表现为进行性肾纤维化。 因此，最近我们重点研究了一种新的蛋白质，称为Deptor，它是mTOR和 是mTORC1和mTORC2活性的负性调节因子。第一次，我们展示了肾脏 在糖尿病患者和糖尿病啮齿动物中，Deptor的表达显著降低。这一削减 有助于增强mTOR活动。我们还发现，高糖和TGFb都能降低血管内皮细胞的活性。 Deptor在系膜细胞和PTE细胞中的表达。我们鉴定了一种microRNA，miR-181a，它在 对高糖或TGFb的反应，调节Deptor的下调。最近，我们发现了一个 涉及PRC2(多梳抑制物复合体2)成分增强子的独立表观遗传机制 ZEST同系物2用于高糖诱导的代谢抑制。我们计划使用这两种机制来 以啮齿动物模型研究糖尿病肾病的并发症。此外，我们还发现了一种新的串音 高糖/TGFb和PDGFRb在系膜和PTE中的激活 细胞。PDGFRb抑制剂阻断了肥大和基质蛋白的表达，表明这一点可以利用 治疗对改善糖尿病肾病的作用。糖尿病与肾癌(RCC)有很强的相关性 已经建立了。我们还鉴定了两个与糖尿病肾病相关的microRNAs，miR-21和miR-214 有助于mTORC1的激活，促进肾癌细胞的增殖和侵袭。因此，目标是 我们研究的重点是探讨糖尿病肾病和肾癌进展的分子机制，并确定 可以被小分子药物和基于抗miR的治疗靶向的信号分子。

Diabetes is the number one cause of end stage kidney disease and accounts for approximately 47% of cases in the US. More than 34 million Americans have diabetes. It is prevalent in the people aged 18 years and older. The demographic of Veteran population falls in this age group. In Veterans aged 65 years and older, approximately 27% are afflicted with diabetes. A recent study demonstrated that diabetic patients with kidney disease had 87% higher risk of cardiovascular mortality. One in three patients with diabetes develop diabetic nephropathy (DN). Early pathologic changes in DN involve renal, especially glomerular hypertrophy and expansion of matrix proteins. The focus of our research is to investigate the signal transduction mechanisms that lead to the progression of DN. To test our concepts, we use both renal glomerular mesangial and proximal tubular epithelial (PTE) cells in culture and, mouse and rat models of diabetes exhibiting kidney pathologies. In kidney, high levels of transforming growth factor-b (TGFb) mediate many pathologic effects of hyperglycemia. Therefore, along with the effects of high glucose, we investigate the signaling mechanisms of TGFb in mesangial and PTE cells. We were the first to discover that high glucose decreases the expression of the tumor suppressor protein PTEN (phosphatase and tensin homolog deleted in chromosome 10) in these cells and in the renal tissues of diabetic mice and rats. We identified that this effect of high glucose is mediated by TGFb. In investigating the mechanisms, we for the first time reported that multiple microRNAs such as miR-21, miR-26 and miR-214 that are significantly increased in the diabetic kidneys regulate the hyperglycemia- and TGFb- induced inhibition of PTEN. In fact, we showed that this inhibition of PTEN expression resulted in sustained activation of Akt kinase that led to activation of mTORC1 (mechanistic target of rapamycin complex 1). mTORC1 contributes to mesangial and PTE cell hypertrophy, and expression of matrix proteins fibronectin and collagen I a2 causing renal hypertrophy and fibrosis in DN. Indeed, we showed that rapamycin ameliorated complications of DN including albuminuria in type 1 and type 2 diabetic mice. Since increased expression of above-mentioned microRNAs contribute to PTEN inhibition/Akt kinase-mediated mTOR activation, our studies opened the door to the novel application of anti-miR therapy for DN. Rapamycin-mediated complete inhibition of mTORC1 causes deleterious clinical outcome. Proximal tubular loss of mTORC1 in mice showed progressive renal fibrosis. Therefore, more recently we have focused on a novel protein, called deptor, which is a component of mTOR and is a negative regulator of both mTORC1 and mTORC2 activities. For the first time, we showed that the renal expression of deptor was significantly reduced in humans with diabetes and in diabetic rodents. This reduction contributed to enhanced mTOR activity. We also found that both high glucose and TGFb decrease the expression of deptor in mesangial and PTE cells. We identified a microRNA, miR-181a, which is increased in response to high glucose or TGFb, regulates the downregulation of deptor. More recently, we identified an independent epigenetic mechanism involving the PRC2 (polycomb repressor complex 2) component enhancer of zeste homolog 2 for high glucose-induced deptor suppression. We plan to use both these mechanisms to target the complications of DN in rodent models. Furthermore, we have identified a novel cross-talk between high glucose/TGFb and PDGFRb (platelet-derived growth factor receptor-b) activation in mesangial and PTE cells. PDGFRb inhibitor blocked hypertrophy and matrix protein expression, indicating that this can be utilized therapeutically for amelioration of DN. A strong correlation between diabetes and renal cell carcinoma (RCC) has been established. We have identified two microRNAs, miR-21 and miR-214, which are involved in DN, also contribute to the activation of mTORC1 and, proliferation and invasion of renal carcinoma cells. Thus, the goal of our studies is to investigate the molecular mechanisms of the progression of DN and RCC, and identify signaling molecules that can be targeted by small molecular drugs and anti-miR based therapies.